Real-time location (RTL) systems have become popular in recent years. Some conventional RTL systems typically use radio frequency (RF) transmissions between a portable tag attached to an asset and plural fixed points to determine location via a trilateration method. Other known RTL systems include fix mounted infrared (IR) or ultrasonic (US) base stations (a/k/a “monitors”) that transmit an ID code using a secondary technology such as infrared (IR) or Ultrasound (US) signals. The IR or US signal includes a respective monitor device ID. Upon reception of a monitor device ID, the portable tag transmits both the portable tag ID and the received monitor device ID (“location data”) to a network access point, for example, by wireless RF transmission such as Wifi 802.11. The access point forwards the received information to a server that uses the monitor device ID and the portable tag ID to determine the location of an asset to which the portable is attached.
In this manner, the position of the portable tag may be displayed as the position of the IR monitor device. Such a system is described, for example, in the incorporated U.S. Pat. No. 8,604,909.
Present day available wireless protocols include Wifi (802.11-type) and alternate RF technology. Alternate RF technology refers herein to communication technology that is not WiFi (802.11-type) based, but which utilizes other RF protocols and/or standards (including, but not limited to: Bluetooth Low Energy (BLE) and Bluetooth, Zigbee, and ZWave), or one of the many non-standardized and available protocols that operate, for example, at 433 or 900 MHz.
Wifi is often preferred because, among other reasons, it allows use of a facility's existing infrastructure when the RTL system is installed. By having the portable tag transmit the location data to the facility's existing Wifi network using the existing Wifi protocol, installation of an entirely new network infrastructure for the sole purpose of implementing the RTL system is avoided.
However, alternate RF technologies are often better suited for RTL applications. For example, such alternate RF technologies consume less power, and allow for smaller tags and longer battery life. Therefore, there exists a need for an RTL system that obtains the benefits of Wifi, so that a facility's existing infrastructure can be used, but which also obtains the benefits of alternate RF technologies.